There is an ongoing trend in the reduction of total ownership cost (TOC) of transformers. This is especially of vital importance for oil-immersed distribution transformers as they constitute major part of the global power infrastructure. Due to their proximity to the customers and the importance of maintaining supply, these transformers are rarely operated under full-load conditions and hence contribution of no-load loss (or equivalently core loss) in the total transformer lifetime loss is significant. A major influence on the TOC of oil-immersed distribution transformers is the no-load or core loss. Another factor influencing the TOC is the transformer material cost. Further, compactness of the transformer is also desired.